Thermal power generation



Sept. 29, 1953 MERCIER ET AL 2,653,443

THERMAL POWER GENERATION 1 Filed Oct. 25, 1949 s Sheets-Sheet 1INVENTORJ Erna! fiferaer BY fiarcel llrlrgjer,

HTTOR/VEY P 1953 E. MERCIER ET AL 2,653,443

THERMAL POWER GENERATION Filed Oct. 25. 1949 3 Sheets-Sheet 2 E? HFI fiv T s i \E l 1%. i I

. i L l 2E 1 INVENTORS Ernzsl fielder BY Marcel 71104 engines.

Patented Sept. 29, 1953 UNITED STATES PATENT OFFICE THERMAL POWER,GENERATION Georgia Application October 25, 1949, Serial No. 123,476 InFrance October 28, 1948 22 Claims. 1

This invention relates to a power generating plant and method ofoperating the same. The invention more especially relates to theproduction' of power in heat utilizing prime movers or The invention inits basic concept particularly relates to the production of power in gasutilizing prime movers and to improvement in a gas thermal cycle. In itsmore specific embodiment the invention also utilizes vapor generatingand heating means and a vapor utilizing prime mover for improvement ofthe overall thermal cycle.

It is a feature of the invention that the main or power producing gasutilizing prime mover is supplied with hot gases at a suitable pressurewhich may be a medium pressure of the degree- .of 20 'kg./cm. In thecycle in which this prime mover is utilized the medium pressure gaseswhich are supplied to this prime mover are pro vided at least in part byproducing high pressure gases, for example, at 100 kg./cm. and expandingthesegases in an auxiliary gas utilizing prime mover to the mediumpressure. Another part of the gases at medium pressure may be supplieddirectly to the main gas utilizin prime mover from a suitable combustionchamber and may be produced by the combustion of fuel in such combustionchamber. The auxiliary gas utilizing prime mover provides at least apart of the power required to compress the combustion supporting gas,ordinarily atmospheric air, to the high pressure required for thecombustion gases to be supplied to the auxiliary gas utilizing primemover. This auxiliary gas utilizing prime mover also may supply at leasta part of the power to compress the combustion supporting gas or air tothe mediumpressure for supporting the combustion of fuel at this mediumpressure to produce the hot gases which are supplied directly tothe maingas. utilizing prime mover. Supplementary power which may be necessaryfor driving the compressors for compressing the combustion supportinggas or air maybe provided by internal combustion engines. Preferablythegas compressors, the auxiliary gas utilizing prime. movers and theinterna1 combustion engines are free piston engines and in the preferredembodiment of these engines they are of the oscillator type in which atleast one oscillatable ,elementoscillates,upon an axis and is providedwith members acting as pistons within fluid pressure chambers.Forsimplicity in the following description the main gas utilizing primemover will be referred to as a gas turbine and the compressors as aircompressors.

It is a further feature of th invention in car rying out'the improvedoperating cycle that the high pressure combustion supporting air beforebeing admitted into the auxiliary gas utilizing prime mover is heated bymeans of a combustion chamber supplied with fuel to increase thetemperature of this air to a reasonably high temperature, say 700 C. Thecombustion of fuel in this chamber may be supported by supplying atleast a part of the high pressure air to the combustion chamber. The hotgases thus produced in the combustion chamber at high pressure which arethen supplied to the auxiliary prime mover are expanded therein and theexpanded or exhaust gases from this gas utilizing prime mover arecarried to the turbine for developing power therein. Before beingadmitted into this turbine, however, preferably these gases are heatedto a reasonably high temperature, say 700 0., by the heat of thecombustion which produces the combustion gases at the medium pressurewhich are supplied directly to the gas turbine. This combustion chambermay be supplied with compressed =air produced in a section of thecompressor at the medium pressure, e. g. 20 kg./cm. the same as theexhaust gases from the auxiliary prime mover.

Since the high pressure gases are supplied to the auxiliary prime moverat a temperature of 700 C. it is necessary to cool th casing of thisprime mover. To .this end the high pressure air, for-example, kg./cm.may be circulated without noticeable, heat loss through a jacketprovided for the casing of the auxiliary gas utilizing prime mover. Thevery high density of the air at this high pressure insures a high heattransfer coeiiicient so that such circulation of air through the jacketis quite efficient for effecting the cooling of the auxiliary primemover and for heating the high pressure air.

This high pressure air may be further heated in a separate heatexchanger through which the air is passed asit flows to the combustionchamber in which the gases which are supplied to the auxiliary primemover are produced. This heat exchanger may be heated by the exhaustgases from an internal combustion engine which cooperates with theauxiliary gas utilizing prime mover in driving the air compressors.These gases at this exhaustpressur when leaving the heat exchanger aredelivered to a corresponding pressure stage of the gas turbine in orderto develop power from their remaining thermal and dynamic energy.

As will be more clearly understood in connecticn with the description tofollow taken in connection with the drawings the air compressor may beconstructed in sections which will produoe compressed air at thedifferent pressures which have been referred to above as Well as atother pressures. The air thus may be compressed in stages in which thepressure is raised substantially to th different pressures at which itis utilized in the system. The internal combustion engine thus also maybe supplied with comressed air for supercharging.

Supplementing the gas utilizing power generating plant above described,in accordance with the invention vapor or steam generating means may beprovided for generation of vapor by the heat of the combustion whichproduces the high pressure high temperature gases which are supplied tothe auxiliary gas utilizing prime mover. This vapor or steam also may besuperheated by the heat of this combustion. The vapor or steam thusgenerated and heated may be supplied to a vapor or steam utilizing primemover for developing power therefrom. For simplicity this prime moverwill be referred to as a steam turbine. Such a steam turbine may bemounted on the same shaft or may be otherwise mechanically connected tothe gas turbine to cooperate therewith for developing the useful power.

In another aspect of the invention steam may be extracted or withdrawnfrom the steam turbine and reheated by the heat of the combustionchamber in which are produced the gases at me dium pressure which aresupplied to the main turbine. This reheated steam may be returned to thesteam turbine for further expansion thereof before discharge to theusual condenser.

The condensate from this condenser may be delivered to steam generatingmeans associated with the combustion chamber which produces the highpressure gases supplied to the auxiliary gas utilizin prime mover forgenerat ng steam therefrom. Preferably this condensate is first reheatedin the convent onal manner by steam bled from the steam turbine. Inorder to pro-- vide the re uisite cool ng medium for the .iacketconventionally provided in the internal combustion en ine which suppl espart of the power for the air compressors. a part of this con ensate orthe condensed bled steam may be d livered to th s "acket for flowtherethrough. In this iacket steam m y be generated fro this cool ngmedium and ma be supe heated in a heat exchan er throu h wh ch thexhaust gas s from the internal combustion engine flow as they aredelivered toward the reduced pressure sta e of the main gas utilizingprime mover or turbine. The steam thus generated and superheated may hedeli ered to a reduced pressure sta e of the steam turbine for e elopingpower therefrom be o e disch area to the condenser.

The in ention will b further understood from the escription to fnunwtaken in connection with the drawin s in which Fig. 1 is a sim lifieddia ram of the power generating plant of the invention;

Fig. 2 is. an entropy diagram showing difierent aspects of the thermalcycle of the invention;

' 3 shows diagrammatically the novel gas lng power generating plant ofthe inven- Fig. 4 is a section on line 44 of Fig. 3;

Fig. 5 is a section on line 55 of Fig. 3;

Fig. 6 show-s a modification of the power generating plant of theinvention which includes steam generating and steam heating apparatusand a steam utilizing prime mover.

In Fig. 1 an internal combustion engine 2 drives an air compressor 3which discharges high pressure compressed air, for example, at apressure of kg./cm. to the conduit 5 leading to a combustion chamber 1.An air compressor 9 driven by a gas utilizing prime mover I I alsosupplies compressed air to the conduit 5 for delivery to the combustionchamber 1. The combustion chamber 1 may be supplied with fuel to producecombustion gases at high pressure, for example, 100 kg./cm. which aredelivered through the conduit l3 to the auxiliary gas utilizing primemover I! for expansion therein to develop the power for driving thecompressor 9.

The gases exhausted from the auxiliary gas utilizing prime mover I l arecarried through the conduit I5 to a combustion chamber 5'! which may besupplied with fuel to produce therein combustion gases at mediumpressure corresponding to the pressure of the exhaust gases from theprime mover H, for example, 20 kg./cm. The gases produced in thecombustion chamber I! at this pressure are carried through the conduit[9 to a gas turbine 2! for expansion therein and discharge therefrom,for example, at atmospheric pressure. The combustion chamber 5! also issupplied through the conduit 23 with compressed air from the compressor9 at the requisite medium pressure to support combustion therein forproducing the gases in the combustion chamber H. It will be understoodthat the exhaust gases from the auxiliary prime mover H thus may bereheated in the combustion chamber ll before being admitted into the gasturbine 2!. The temperature to which the combined gases, namely thoseproduced by combustion of fuel in the combustion chamber H and theexhaust gases from prime mover H may be raised may be of the degree of700 C. when the pressure of the gases produced in the combustion chamberI1 is, for example, 20 kg./cm.

In the entropy diagram of Fig. 2 are shown several aspects of thethermal cycle which may be carried out in the power generating plantdiagrammatically shown in Fig. 1 and further described hereafter.

The cycle shown in full lines abcdefghe'a relates to the air and gaseswhich are produced at high pressure and temperature and are expandedfrom such high pressure, for example, 100 kg./cm. to the mediumpressure, 20 kg/cmfi, then are reheated and further expanded to atmosheric pressure.

The cycle represented in dash lines aka'lmmz represents the cycle forease: produced at a medium pressure. for example 20 kg./cm. if thesegases were not cooled by admixture there th. as above mentioned, of theexhaust gases from the au iarv rime mover l I.

The c cle in dotted line aors a represents the cycle of the internalcombustion engine supplied with a r at supercharging pressure.

In Fig. 2. by way of example, the lines of constant pressure are shownrepresenting 1 kg/cm. or atmos heric pressure and the pressures of theseveral pressure stages develo ed in the compressor. In the full linedia ram the air at atmospheric pressure is compressed first to 10ken/cm. alon the line ab corres onding to polytropic compression notreatly different from isothermal compression. This may be acco plishedbv the atomi ation of water within the compression chambers of thecompressors in a manner and by means not shown which in themselves arenotpart of this invention. The air thus compressed at '10 vl-:g./cm;"iscooled along the line bc'which may beaccomplishedby arconventionalinteroooler. This air then is cornpressed in a second stage ?from .10ks/cm. to 100 kg./cm. along the line cd representing a polytropiccompression which departs substantially from the isothermal in order toobtain a final temperature of about 150 C. .in the example illustratedin Fig. 2 which substantially corresponds to maximum efficiency. The airat this .high pressure then may be circulated, as described generallyabove, through the jacket of the auxiliary gas utilizing prime'mover Hand thereafter may be further heated 'by fiow through a heat exchangeras will be described in connection with Fig. 2 which may receive heatfrom the exhaust gases from the internal combustion engine. This heatedair may be further heated by mixture with the gases produced within thehigh pressure combustion chamber 1 and then supplied to the auxiliaryprime mover II for development of power therefrom. Heating of the air at100 kg./cm. is indicated by the isobar de in Fig. 2. Adiabatic expansionof these high pressure gases from a temperature of approximately 700 C.in the example of Fig. 2 in the auxiliary gas utilizing prime mover IIis indicated along the line ef to the medium pressure, 20 kg./cm. Thegases exhausted from the auxiliary prime mover at this medium pressureagain are heated, as above indicated, in the combustion chamber I! alongthe isobar fg to a temperature of approximately 700 C. The secondadiabatic expansion which is accomplished in the gas turbine?! isindicated by the line gh to atmospheric pressure, 1 kg./cmi at whichpressure the gases are exhausted along the isobar ha, to close the fullline diagram.

In the diagram shown in dash lines a twostage compression is representedfirstfrom the atmospheric pressure to 4.4 kg./cm. along the line ale.Intercooling is represented by the line icy and the second stagecompression from 4.4 kg./cm. to 20 kg./cm. is represented by the linea'l. The air thus compressed is heated along the isobar Zm at 20 kg./cm.In this diagram this heating is not stopped at the final temperatureof'700 C., which, for example, may be determined by heating resistingmaterials available for the purpose, but at the temperature which wouldbe reached if the mixture of the exhaust gases from the auxiliary gasutilizing prime mover H withv the combustion gases produced in thecombustion chamber ll had not been effected. This temperature then wouldhave risen to a temperature of the degree of 1200 C.

In the diagram in dotted lines the compression of the air for theinternal combustion engine-2 from atmosphere to 3.5 kg./cm. assumed asthe supercharging pressure is represented by the adiabatic up, thecompression within the internal combustion engine to 80 kg./cm.beingcon- Itinued along the diabatic c. Heating of the compressedcombustion gases within internal combustion engine by the combustion ofthe fuel supplied thereto is represented along the isobar qr andexpansion of thegases in the power stroke of the internal combustionengine is represented along the adiabatic rs again to the superchargingpressure 3.5 kg./cm. The cooling of the ases exhausted from the internalcombustion engine by heating the air supplied to the high 6 pressurecombustion chamber or, in the modified power generating plant, bysuperheating the steam generated in the jacket of the internalcombustion engine is represented by the isobar sp. Expansion of theseexhaust gases in the gas turbine I9 is effected along the adiabatic pa.

From the entropy diagram with the aid of conventional tables thedifferent amounts of energy utilized and the final efficiency of thecycle may be determined'without difiiculty. In such determinations it isnecessary to bear in mind that the air quantities which are involved inthe three different cycles hereinabove described are not the same butdepend upon the selected final temperature and the selected power of thegas and internal combustion engines. The mass of air at 20 kg./cm. willdepend on the final temperature of this air after heating. It will besmaller according as this temperature is increased. At the same time themass of air at 3.5 kg./cm. will depend directly on the power which ischosen for the internal combustion engine. By judicious choice of thevarious elements it will not be difficult to arrive at a condition wherethe quantities of air at 20 kg./cm. and of the supercharging air at 3.5kg./cm. both have, for example, a value equal to half the value of theair mass compressed to kg./cm.

From the point of view of final efiiciency as well as from that ofsimplicity of the equipment, compressors of the free piston type arepreferred more particularly those of the free oscillator type. Forimprovement of efiiciency also part of the heat otherwise lost bycooling of the internal combustion engines may be recovered bycirculating water under sufficient pressure, for example, 5 kg./cm. andevaporating a part of this water in the jacket of these engines inaccordance with a prior proposal of the applicants. t may be advisablein certain cases from the standpoint of final efiiciency to effectcooling of the internal combustion engines by means of air compressed bythe apparatus to 100 kg./cm. or to 20 kg./crn.

In Fig. 3 the essential elements of' the basic gas utilizing powergenerating plant are shown for carrying out the cycle of Fig. 2. In Fig.3 the prime mover compressor unit 23 comprises a low pressure compressorsection and a high pressure compressor section driven by an auxiliaryprime mover utilizing gases at high pressure and temperature and alsodriven by an internal combustion engine, all of these elements in theembodiment of Fig. 3 being oscillating free piston fluid pressuremachines with the oscillating members thereof supported for oscillation'on a common axis and mechanically connected together for eiiectingcompression of the air upon oscillating movement of the compressormembers produced by the oscillating movement or" the prime mover membersof this unit. All of these elements, as will be understood more clearlyfrom the more detailed description to follow of the compressor sections,may be constructed, for example, with eight chambers in whichrespectively vanes carried by the respective oscillating membersreciprocate, the compression cf the air to the several pressuresrequired for the cycle described in connection with Fig. 2 being accomplished in the different chambers of the low pressure and of the highpressure sections of the compressor. The expansion of the hightemperature high pressure gases and of the gases produced in theinternal combustion engine is effected in similar chambers respectivelyof the auxiliary prime mover and of the internal combustion engineconcomitantly with reciprocation in these chambers of the vanes of theseprime movers.

In Fig. 3 a low pressure section 25 of the air compressor receivesatmospheric air through the intake This compressor, being of theoscillating type comprises, as shown more or less diagrammatically Fig.an oscillating mernber '25:- supported for oscillation upon its axis andprovided with vanes outwardly extending therefrom respectivelyreciprocating within compression chambers formed within a casing 3ibetween inwardly extending sectors 33. The two oppositely disposed vanes35 reciprocate within the respective chambers for compression of the airfrom 1 lzg/crn. to 3:5 kg./crn. two oppositely disposed vanes 35reciprocating Within the respective chambers ti compress the air fromfour vanes reciprocating in the four chainbers b": npress air 1 kg/cm.to is leg/cm. in the stage the two-stage compression for producing air16o lrg/cn For simplicity the requisite connections between the chambersthe valve gear for controlling the air as it is being compressed and forcontrolling delivery thereof f om the low pressure section of thecompressor are not shown in 4. It will be apparent, nevertheless, thatthe compressed air may be discharged from the respective chambers at thepressures requisite for supercharging the internal combustion engine aswell as for further compression in the high pressure section 55 of thecompressor. it will be noted consistent with the above description ofthe particular cycle represented in Fig. 2 that in the low pressuresection 2-? two chambers are provided com- A ression of the air fror. ileg/cm. to 3.5 kg./cm. two chambers are provided for compression fromkgx/cm. to 4.4 leg/cm. and four chambers are provided for compressionfrom 1 kg/cin. to 10 kg/cm.

Through the pipe 5 air compressed in the low pressure section 25 of thecompressor to 10 kg/cm. is delivered to the hi h pressure section of thecompressor for compression therein to 10s lag/cm? As shown in Fig. 5which is a section on line 5-5 of Fig. 3, the high pressure section isconstructed similarly to the low pressure section as an oscillating freepiston compressor and is similarly provided with four chambers 5% inwhich vanes carried by the oscillating member reciprocate, these fourchambers providing for compression to 16-0 kg/cin. of the air firstcompressed in the low pressure section to 10 kg/cm. Through another ipe58 air compressed in the low pressure section to 4.4 leg/cm. isdelivered to the other four chambers t l of the high pressure section 55to be compressed therein to so leg/cm. by vanes It will be understoodthat in some cases the air quantities required may not be exactly in theratio of 2 to 1 assumed in the above discussion. Variation, however, maybe made to meet different conditions varying the amount of clearancebetween the vanes on the oscillatable mem bers and the sectors whichprovide the end walls of the chambers in which these vanes reciprocate.Moreover, it is possible to construct the oscillating free pistonmachines which chambers of different radial extent and withoorresp0ndingly different radial dimensions of the vanes reciprocatingtherein.

The compressed air at high pressure, 100 kg./cm. is delivered from thehigh pressure section 55 through pipe 61 to the jacket of the auxiliarygas utilizing prime mover 553 which supplies part of the power fordriving the air compressors 25, 55 to effect cooling of this auxiliarygas utilizing prime mover and heating of this high pressure air. Thisair is then delivered to the annular space as between the jacket 65 andthe gas supply pipe 6? carrying high pressure high temperature gases tothe auxiliary gas utilizing prime mover 63 and is further heated in thisjacket. As shown in Fig. 3 the annular space 64 is connected to theannular space 63 formed between the double walls extending about acombustion chamber 69 so that the compressed air after passing throughthe jacket of the auxiliary prime mover 63 and through the jacket 65passes through the annular space 68 and is heated therein whilepreventing undue loss of heat from the combustion chamber walls. Thishigh pressure air thus heated continues through the pipe H to a space atone end of a tubular heat exchanger l3 supp ied with heating gases ashereinafter described for flow through the tubes 15 of this heatexchanger to the space at the opposite end thereof from which the pipeI? leads to carry the high pressure air thus further heated in the heatexchanger 53 to the combustion chamber 69 for support of combustiontherein of fuel supplied to the combustion chamber through the pipe it.The heat thus added to the air at high pressure, e. g. 100 kg./cm. maybe such as to bring its temperature to say 700 C. as explained inconnection with Fig. 2. These high pressure high temperature combustiongases are expanded in the auxiliary gas utilizing prime mover drivingthe compressor sections and are exhausted therefrom at 20 kg/cm. throughthe pipe which conducts these gases to the combustion chamber 85.

This combustion chamber is supplied with fuel through pipe 8! forproducing combustion gases therein at the medium pressure, namely, 20kg./cm. in the example under discussion. From the chambers of the highpressure section 55 of the compressor-in which air is compressed from4.4 kg/cm. to 20 kg./cm. the compressed air at 20 kg/cm. is deliveredthrough the pipe =36 to a jacket 9! forming an annular space 92 about apipe 93. From the combustion chamber combustion gases at the mediumpressure are delivered through pipe 93 to the main gas utilizing primemover 95 which in the embodiment illustrated in Fig. 3 is a gas turbine.The compressed air at the medium pressure flows through space 92 of thejacket 9! and through annular space 86 provided by the spaced walls ofthe combustion chamber 85 and through the pipe 9'! into the combustionchamber 85 adjacent the burner for supporting combustion of the fuelsupplied by the fuel pipe 8? to produce gases at the medium pressure. Itthus will be apparent that the gases supplied to the turbine 8 5 throughpipe 93 comprise the gases produced directly by combustion of the fuelat the medium pressure as well as the gases exhausted from the auxiliarygas utilizing prime mover 6-3 at the medium pressure, 20 kg./cm. In theembodiment of Fig. 3 the gases from the turbine 95, after expansionthereof, are exhausted to atmosphere through the pipe 99.

From the chambers of the low pressure se tion 25 of the compressor inwhich the air is compressed to 3.5 kg/cm. air is delivered through thepipe I to the internal combustion engine IIII for supercharging theinternal com-. bustion engine. The exhaust gases leaving this internalcombustion engine substantially at the pressure of 3.5 kg./cm. flowthrough the pipe I03 to the space about the tubes I5 of the heatexchanger '13 to heat the high pressure compressed. air flowing throughthese tubes as above described. The exhaust gases then are dis-v chargedfrom the heat exchanger 13 through the pipe I05 and are delivered to areduced pressure stage of the gas turbine 95 for expansion therein toatmospheric pressure as referred to above in the description inconnection wi h the entropy diagram in dotted lines in Fig. 2.

It will be understood in accordance with con-,1v ventional practice thatintercoolers may be pro-1 vided between the stages of compressioneffected by the low pressure and high pressure sections of thecompressor for eiiecting cooling, as indicated above in connection withFig. 2, of the air compressed in a lower stage before further com-vpression thereof in a higher stage. Such inter? coolers if required maybe connected, for exam; ple, in the pipes 5i and 59 of Fig. 3.

In Fig. 6 is shown a modification of the power generating plant of Fig.3 in which the combus-.

ti on chambers 69 and 85 respectively also serve.

for generating and superheating vapor, such as steam from water, and forreheating such vapor or steam for expansion thereof in a steam turbine,the reheated steam being delivered again to the turbine for furtherexpansion in the reduced pressure stage thereof. In Fig. 6 for the mostpart the corresponding elements and members of the apparatus areidentified by the same reference numerals as in Fig. 3. Thus in Fig. 6the air compressed in the low pressure section of the compressor 25 isdelivered through the pipe 59 at 4.4 k-g./cm. to the high pressuresection 55 tobe compressed therein to 2G kg./cm. and then is deliveredthrough the pipe 89 to the jacket 9| surrounding the gas supply pipe 93leading to the gas turbine 95. The compressed air at 20 kg./cm. isheated in passing along the annular space 92 of the jacket 0| by thegases flowing from the combustion chamber 85 through the pipe 93 to theturbine 95. The air at this pressure thus heated is delivered to theburner III for support of the combustion of the fuel supplied to thisburner by the pipe 87. Similarly to the embodiment of Fig. 3 through thepipe 8I the exhaust ases from the auxiliary gas utilizing. prime mover63 driving the air compressors also is delivered to the combustionchamber 85 at the medium 10 kg./cm. is delivered through the pipe 5'! toi the high pressure section 55 to be compressed to 100 kg./cm. Air atthis high pressure is delivered through the pipe 6| to the jacket of theauxiliary prime mover 63 and discharged from this jacket to the jacket65 surrounding the pipe 6'! which carries the hot high pressure gasesfrom the combustion chamber 69 to the auxiliary primev mover 63.

The air at high pressure from the jacket 65., as

in the embodiment of Fig. 3, is delivered through pipe II and throughthe tubes of the heat exchanger I3' and through the pipe TI to theburner II3. to which through the pipe I9 fuel is supplied for combustionthereof in the combustion chamber 65. The combustion gases thus producedat high pressure of the degree of kg/cm. in this example are expanded inthe auxiliary prime mover through pipe GTI. As above stated the exhaust,gases at 2Q. kg./cm.3 from the auxiliary prime mover 55 are deliveredthrough pipe ill to the combustion chamber 85.

As in Fig. 3 supercharging air is supplied at 3.5 kg./crn. to theinternal combustion engine IIJI through the pipe 10 from the lowpressure section 25 of the compressor. The exhaust gases from theinternal combustion engine ItI in this embodiment are delivered at 3.5kg./cm. through the pipe I 2i to the heat exchanger 13 for heating theair at high pressure flowing through tubes I5 of this heat exchanger.The gases upon discharge from the heat exchanger "I3 are carried throughpipe I05 to a reduced pressure stage of the. turbine 95 for furtherexpansion therein.

In the embodiment of Fig. 6 the high pressure combustion chamber 69 isprovided with a Water Wall enveloping this chamber to which through pipeI27 the condensate from a condenser IEQ, receiving the steam from thesteam turbine ISI is, delivered. Although not shown in Fig. 6 theconventional banks of tubes or other means for absorbing heat from thegases also may be provided within the combustion chamber 5% forgenerating steam from the water received through pipe I21 and forsuperheating this steam. This superheated steam may be carried throughpipe I33 to a high pressure stage of the turbine I35 for expansiontherein to the condensing pressure and discharge of the steam at thispressure to the condenser I29 to produce the condensate. This condensateis carried through the pipe I35 to conventional water heaters I3fi, I3?which are heated by steam bled from the turbine I3I, the steam condensedin the heaters I35, I3? being returned through pipes I38, I39 to thewater flow pipes to be mixed with the condensate from the condenser I29.

Steam may be bled from the turbine, for example at 5 kg./cm. for heatingthe condensate in the heater I36 to C. this heated water being deliveredthrough the pipe MI to the jacket or the internal combustion engineI-III for effecting cooling of this internal combustion engine. Steam isgenerated from this waterin this jacket and is carried through thejacket l23 surrounding the exhaust pipe I2! in which jacket it issuperheated for extracting heat from the exhaust gases from the internalcombustion engine. This superheated steam then is carried through thepipe I43 to a reduced pressure stage of the steam turbine ISI forexpansion therein to the condense ing pressure.

Enveloping the combustion chamber 85 operating at the, medium pressureof 20 kg/cmfi, or in conventional arrangements to. receive the heat ofthe combustion chamber, steam carrying passages are provided. Steamextracted from a reduced pressure stage of the steam turbine I3! is careo h. t e pe n. o hese a a e r the combustion chamber 85 for reheatingtherein and return through the pipe I53 to an adjacent stage of thesteam turbine ItI for further expanheat for raising the temperature ofthe gases to that requisite for delivery to the auxiliary prime mover,which requires only a part of the oxygen in the high pressure airdelivered to the combustion chamber, may develop heat to heat the waterfor generating steam and for superhcating this team. This steam may beand preferably is generated at a pressure of the same degree, e. g. 100kg./cm. as that of the combustion gases produced in the combustionchamber 69. Power generating plants utilizing combustion chambers thusoperated at equipressure are disclosed in our Patent No. 2,e66,'i23,April 12, 1949, and in a coending application of Ernest Meroier SerialNo. 472,217 filed January 13, 1943, now abandoned, and in a cop-endingapplication of Ernest Mercier Serial No. 103,893, filed July 9, 1949,now Patent No. 2,547,135, which latter is a continuation in part of thesaid application Serial No. 472,217.

It will be understood, although the jacket 65 surrounding the pipes 67and the jacket 9! surrounding the pipe 93 are not shown in Fig. 6extending the full length respectively of the pipes 6i and 93, thatthese jackets may be of any desired length and if desired may cover thefull length of the pipes from the outlet connection from the combustionchambers es and respectively to the auxiliary prime mover S3 and the gasturbine 95 in order to prevent loss of heat from these pipes and torecover therefrom heat for heating the high pressure air and for heatingthe medium pressure air for the combustion of the fuel in the respectivecombustion chambers.

It will be understood further that within the scope of the invention tosuit different conditions various combinations of the steam generatingand steam reheating apparatus with the gas generating and gas utilizingapparatus may be used. For example, in Fig. 6 the reheating of steamextracted from the steam turbine may be omitted, the gases at the mediumpressure being produced in a combustion chamber in the manner shown anddescribed in connection with Fig. 3 for supply of these gases to the gasturbine. The cooling of the internal combustion engine also may beaccomplished without the generation of steam or without the superheatingthereof in the heat exchanger represented by the pipe iEi and the jacket23. The air compressed at medium pressure may be heated by the exhaustgases from the internal combustion engines.

Other variations may be made without departing from the main inventiveconcept according to which a gas utilizing prime mover, such as a gasturbine, is supplied with hot gases at medium pressure, a part of whichgases may be and preferably are supplied by the exhaust from anauxiliary gas utilizing prime mover supplying at least a part of thepower for driving the air compressor, this air compressor supplying airfor support of combustion directly to produce gases at the mediumpressure for expansion in the gas turbine and also supplying air forsupport of combustion at high pressure to produce high pressure hightemperature gases for supplying the auxiliary prime mover to developpower therefrom.

It will be understood that liquid or colloidal fuels or solid fuel(powdered coal) may be burned in the respective combustion chambers '5',l'i, 69, 85 for developing heat in these combustion chambers.

In a further modification within the scope of the invention instead ofusing water in the jacket of the internal combustion engine for coolingthis engine, compressed air, for example at 100 kg./cm. may becirculated in this jacket before being delivered to the combustionchamber. Moreover, the heat remaining in the exhaust gases from the gasturbine may be partially recuperated by heating the air or the water atsuitable points in the cycle. For example, these gases may be used insome cases in a suitable heat exchanger to heat or to aid in heating theair for combustion of fuel to produce the high pressure gases.

In the claims reference is made to main and auxiliary combustionchambers and prime movers for conveniently distinguishing between thecombustion champer supplying the gases to the gas utilizing prime mover,the gas turbine in the embodiment described, which delivers the usefulpower and the combustion chamber which supplies the high pressure gasesto the prime mover supplying power to the air compressors.

We claim:

1. Power generating plant comprising means providing a combustionchamber for combustion of fuel therein, means for effecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas utilizingprime mover connected to said combustion chamber for utilizing the gasestherefrom under said predetermined pressure to develop power in saidprime mover by expansion of said combustion gases, means for compressinga combustion supporting gas to a pressure effective for delivering saidgas to said combustion chamber against the pressure of the combustiongases therein, said combustion chamber being connected to saidcompressing means to receive said compressed combustion supporting gastherefrom without substantial expansion thereof, an auxiliary primemover utilizing gases at high temperature and at a pressure initially inexcess of said predetermined pressure to develop power therefrom byexpansion thereof to an exhaust pressure substantially corresponding tosaid predetermined pressure of said gases in said combustion chamber,said auxiliary prime mover being operatively connected to saidcompressing means for driving said compressing means independently ofsaid main prime mover to effect said compression of said combustionsupporting gas, and means for delivering the exhaust gases from saidauxiliary prime mover driving said gas compressing means to saidcombustion chamber to be delivered therefrom with and to cooperate withsaid gases produced in said com bustion chamber for developing powertherefrom in said main prime mover upon further expansion thereof fromsaid exhaust pressure.

2. Power generating plant comprising means providing a combustionchamber for combustion of fuel therein, means for effecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas utilizingprime mover connected to said combustion chamber for utilizing the gasestherefrom under said predetermined pressure to develop power in saidprime mover by expansion of said combustion gases, means for compressinga combustion supporting gas to a pressure effective for delivering saidgas to said combustion chamber against the pressure of the combustiongases therein, said combustion chamber being connected to saidcompressing means to receive said compressed combustion supporting gastherefrom substantially at said pressure to which it is compressed,

an auxiliary prime mover, means cooperating with said auxiliary primemover to effect utilization of gases at high temperatureand at apressure initially substantially in excess of said predeterminedpressure to develop power therefrom by expansion thereof to an exhaustpressure substantially corresponding to said predetermined pressure ofsaid gases in said combustion chamber,- said auxiliary prime mover beingoperatively connected to said compressing means for driving saidcompressing means independently of said main prime mover to effect saidcompression of said combustion supporting gas, and means for deliveringthe exhaust gases from said auxiliary prime mover driving said gascompressing means to said combustion chamber to be heated by the heat ofthe combustion therein and to be delivered therefrom with and tocooperate with said gases produced in said combustion chamber fordeveloping power therefrom in said main price mover upon furtherexpansion thereof from said exhaust pressure.

3. Power generating plant as defined in claim 1 which comprises aninternal combustion engine operatively connected to said compressingmeans to provide part of the power required for operating saidcompressing means.

4. Power generating plant as defined in claim 1 in which saidcompressing means [and the prime mover driving said compressing meansare. free piston fluid pressure machines.

5. Power generating plant as defined in claim 3 in which saidcompressing means and said auxiliary gas utilizing prime mover and saidinternal combustion engine are free piston fluid pressure machines ofthe oscillator type.

6. Power generating plant as defined in claim 3 which comprisescompressing means connected to said internal combustion engine forsupplying supercharged combustion supporting gas thereto.

7. Power generating plant as defined in claim 1 which comp-rises acooling jacket for said auxiliary prime mover, and means for deliveringcompressed combustion supporting gas from said compressing means throughsaid jacket for cooling said auxiliary prime mover and heating saidcompressed combustion supporting gas.

8'.- Power generating plant as defined in claim 1 which comprises anauxiliary combustion chamber, means for effecting combustion of fuel insaid auxiliary combustion chamber to produce said gases at said hightemperature and at said pressure initially in excess of saidpredetermined pressure, said auxiliary combustion chamber beingconnected to said auxiliary prime mover to deliver said combustion gasesthereto to said exhaust pressure to develop power therefrom by expansionthereof in said auxiliary prime mover.

9. Power generating plant as defined in claim 8 which comp-rises meansfor delivering compressed combustion supporting gas at a pressure of thedegree of the pressure of the gases produced in said auxiliarycombustion chamber to said auxiliary combustion chamber for support ofthe combustion therein.

10. Power generating plant as defined in claim 8 which comprises ajacket enveloping said auxiliary combustion chamber, means fordelivering compressed combustion supporting gas at a pressure of thedegree of the pressure of the gases produced in said auxiliarycombustion chamber to said jacket for flow therethrough for interceptingheat otherwise lost from the walls of said combustion chamber andheating said combustion supporting gas, and means for delivering saidcompressed combustion supporting gas heated in said jacket to saidauxiliary combustion chamber for support of the combustion therein.

11. Power generating plant as defined in claim 1 which comprises a heatexchanger, means for delivering compressed gas at a pressure of thedegree. of. the pressure of said gases at high temperature and. pressureutilized in said auxiliary prime mover to said heat exchanger to beheated therein, means for delivering said heated compressed gas to saidauxiliary prime mover for said power developing expansion therein aninternal combustion engine cooperating with said auxiliary prime moverfor developing power for driving said compressing means, meansconnecting said internal combustion engine to said heat exchanger fordelivering exhaust gases from said internal combustion engine to saidheat exchanger for heating said compressed gas therein, and means fordelivering said exhaust gases from said heat exchanger to a reducedpressure stage of said main prime mover for developing therein powerfrom said exhaust gases.

12. Power generating plant as defined in claim 1 which comprises a heatexchanger, means for delivering compressed combustion supporting gas ata pressure of the degree of the pressure of said gases at hightemperature and pressure utilized in said auxiliary prime mover to saidheat exchanger to be heated therein, an auxiliary combustion chamber,means for delivering said heated compressed combustion supporting gasfrom said heat exchanger to said auxiliary combustion chamber forsupport of combustion therein, means for effecting combustion of fuel insaid auxiliary combustion chamber to produce said gases at hightemperature and at said pressure initially in excess of saidpredetermined pressure, said auxiliary combustion chamber beingconnected to said auxiliary prime mover to deliver said combustion gasesthereto for said power developing expansion therein, an internalcombustion engine cooperating with said auxiliary prime mover fordeveloping power for driving said compressing means, means connectingsaid internal combustion engine to said heat exchanger for deliveringexhaust gases from said internal combustion engine to said heatexchanger for heating said compressed combustion supporting gas therein,and means for delivering said exhaust gases from said heat exchanger toa reduced pressure stage of said main prime mover for developing thereinpower from said exhaust gases.

13. Power generating plant as defined in claim 12 in which said internalcombustion engine is provided with a cooling jacket, a steam utilizingprime mover, means for supplying steam to said steam utilizing primemover to develop power therefrom by expansion of said steam in saidsteam utilizing prime mover, means for condensing steam withdrawn fromsaid steam utilizing prime mover after expansion thereof, means fordelivering the condensate through said jacket of said internalcombustion engine for effecting cooling of said internal combustionengine and for generating steam from said condensate in said jacket,heat exchange means connected between said internal combustion engineand said heat exchanger for flow of the exhaust gases from said internalcombustion engine through said heat exchange means to said heatexchanger, said heat exchange means being connected to said jacket ofsaid internal combustion engine to receive the generated steam therefromfor superl heating said steam by the heat of said exhaust gases.

14. Power generating plant comprising means providing a main combustionchamber for combustion of fuel therein, means for effecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas utilizingprime mover connected to said main combustion chamber for utilizing thegases therefrom under said predetermined pressure to develop power insaid main prime mover by expansion of said combustion gases, means forcompressing a combustion supporting gas to a pressure effective fordelivering said gas to said combustion chamber against the pressure ofthe combustion gases therein, said combustion chamber being connected tosaid compressing means to receive said compressed combustion supportinggas therefrom without substantial reduction of the pressure thereof, anauxiliary combustion chamber for combustion of fuel therein, means foreffecting combustion of fuel in said auxiliary combustion chamber toproduce gases at high temperature and at a pressure initiallysubstantially in excess of said predetermined pressure, an auxiliaryprime mover connected to said auxiliary combustion chamber and utilizingtherefrom said gases at high temperature and at said pressure in excessof said predetermined pressure to develop power by expansion thereof toan exhaust pressure substantially corresponding to said predeterminedpressure of gases in said main combustion chamber, said auxiliary primemover being operatively connected to said compressing means for drivingsaid compressing means independently of said main prime mover to effectsaid compression of said combustion supporting gas, means for deliveringthe exhaust gases from said auxiliary prime mover driving saidcompressing means to said main combustion chamber to be heated thereinand to be delivered therefrom with and to cooperate with said gasesproduced in said main combustion chamber for developing power therefromin said main prime mover upon further expansion thereof from saidexhaust pressure, steam generating means cooperating with said auxiliarycombustion chamber for generating steam by the heat of said combustiontherein, and a steam utilizing prime mover connected to said steamgenerating means to receive therefrom said steam generated therein forexpansion of said steam in said steam utilizing prime mover.

15. Power generating plant comprising means providing a main combustionchamber for combustion of fuel therein, means for effecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas utilizingprime mover connected to said main combustion chamber for utilizing thegases therefrom under said predetermined pressure to develop power insaid main prime mover by expansion of said combustion gases, means forcom.- pressing a combustion sup-porting gas to a. pressure effective fordelivering said gas to said combustion chamber against the pressure ofthe combustion gases therein, said combustion chamher being connected tosaid compressing means to receive said compressed combustion supportinggas therefrom without substantial reduction of the pressure thereof, anauxiliary prime mover utilizing gases at high temperature and at apressure initially substantially in excess of said predeterminedpressure to develop power therefrom by expansion thereof to an exhaustpressure substantially corresponding to said predetermined pressure ofsaid gases in said combustion chamher, said auxiliary prime mover beingoperatively connected to said compressing means for driv ing saidcompressing means independently of said main prime mover to effect saidcompression of said combustion supporting gas, means for delivering theexhaust gase from said auxiliary prime mover driving said compressingmeans to said main combustion chamber to be heated therein and to bedelivered therefrom with and to cooperate with said gases produced insaid combustion chamber for developing power therefrom in said mainprime mover upon further expansion thereof from said exhaust pressure, asteam utilizing prime mover, means for supplying steam to said steamutilizing prime mover to develop power therefrom by expansion of saidsteam in said steam utilizing prime mover, steam reheating means heatedby the heat of said main combustion chamber, means connecting a reducedpressure stage of said steam utilizing prime mover to said steamreheating means for reheating steam withdrawn at said reduced pressurefrom said steam utilizing prime mover, and means for returning saidreheated steam of said reduced pressure from said reheating means to areduced pressure stage of said steam utilizing prime mover for furtherexpansion thereof in said steam utilizing prime mover.

16. Fower generating plant as defined in claim 15 in which said reducedpressure of said steam withdrawn from said steam utilizing prime moveris of the degree of the pressure of the combustion gases within saidmain combustion chamber.

17. Power generating plant as defined in claim 1 which comprises aninternal combustion engine cooperating with said auxiliary prime moverfor generating power for driving said compressing means, said internalcombustion engine being rovided with a cooling jacket, a steam utilizingprime mover, means for supplying steam to said steam utilizing primemover to develop power therefrom by expansion of said steam in saidsteam utilizing prime mover, means for condensing steam withdrawn fromsaid steam utilizing prime mover after expansion thereof, means fordelivering the condensate through said jacket of said internalcombustion engine for effecting cooling of said internal combustionengine and for generating steam from said condensate in said jacket,heat exchange means connected to said internal combustion engine toreceive the exhaust gases therefrom, said heat exchange means beingconnected to said jacket of said internal combustion engine to receivetherefrom the steam generated therein for superheating said steam by theheat of said exhaust gases, means for delivering said exhaust gases fromsaid heat exchange means to a reduced pressure stage of said main gasutilizing prime mover for developing therein power from said exhaustgases, and means for delivering said superheated steam from said heatexchange means to a reduced pressure stage of said steam utilizing primemover for developing therein power from said superheated steam.

'13. Power generating plant comprising means providing a main combustionchamber for combustion of fuel therein, means for eifecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas g-erases:

utilizing prime mover connected to" saidcombustion chamber. forutilizingthegases. therefrom under said predetermined pressure todevelop power. said prime mover by expansion of said combustion gases,means for compressing a combustion supporting gas to a plurality ofpressures, at least a given one ofsaid pressures being effective for.delivering at least aportion of said combustion supporting gas to saidmain combustion chamber against the pressure of theco-mbustion gasestherein, said main combustion chamber being connected. tosaid-compressing means to receive said compressed combustion supportinggas therefrom substantially at said given pressure, an auxiliary primemover utilizing gases at high temperature and at a pressure initiallysubstantially in excess of said predetermined pressure to develop powertherefrom by expansion thereof to an exhaust pressure substantiallycorresponding to said predetermined pressure of said gases in said maincombustion chamber, an internal combustion engine, said auxiliary primemover and said internal combustion engine being operatively connected tosaid compressing mean and cooperating to drive said compressing means asa unit indepe t y of said main gas utilizing prime mover for effectingcompression of said combustion supporting gas, said internal combustionengine being connected to said compressing means to receive therefromcombustion supporting gas at a pressure for supercharging said internalcombustion engine, an auxiliary combustion chamber, means for effectingcombustion of fuel in said auxiliary combustion chamber to produce saidgases at high temperature and at said pressure in excess of saidpredetermined pressure, said auxiliary combustion chamber beingconnected to said compressing means to receive therefrom combustionsupporting gas at a high pressure for combustion of fuel in saidauxiliary combustion chamber at said pressure in excess of saidpredetermined pressure, said auxiliary combustion chamber beingconnected to said auxiliary prime mover to deliver thereto saidcombustion gases at said high temperature and substantially at saidpressure in excess of said predetermined pressure to develop powertherefrom, and means for delivering the exhaust gases from saidauxiliary prime mover to said main combustion chamber to be heatedtherein and to be delivered therefrom with and to cooperate with saidgases in said main combustion chamber for developing power therefrom insaid main prime mover upon further expansion thereof from said exhaustpressure.

19. Power generating plant as defined in claim 13 in which said steamgenerating means is adapted for generating said steam at a pressure ofthe degree of the pressure of the combustion gases within. saidauxiliary combustion chamber.

20. Power generating plant comprising an internal combustion engine, asupercharger air compressor driven by said engine and connected to saidengine to deliver thereto supercharging air at a pressure providing forexhausting the gases from said internal combustion engine at a pressuresubstantially above atmosphere pressure, a high pressure air compressordriven by said internal combustion engine, a high pressure combustionchamber connected to said high pressure compressor to receive highpressure air therefrom for effecting combustion of fuel to producecombustion gases substantially at said high pres- Sure, an auxiliary gasutilizing prime mover oo- 18- operating with said internal combustionengine to' drive said compressors and connected to said combustionchamber to receive therefrom said high pressure combustion gases'forexpansion in said" auxiliary prime mover to a predetermined pressuresubstantially" higher than said exhaust pressureof' said internalcombustion engine, a second combustion" chamber, means for supplyingfuel and air to'- said second combustion chamber for producing thereincombustion gasessubstantially'at said predetermined pressure, said auxiliary' gas utilizing prime mover being connected to said secondcombustion chamber to deliver theretot-he exhaust gases from saidauxiliary prim-emover at said predetermined pressure, a gas turbineconnected to said second combustion chamber to receive therefrom saidcombustion gases produced therein and said exhaust gases heated thereinby the heat of combustion for expansion of said exhaust and combustiongases in said turbine, said internal combustion engine being connectedto a reduced pressure stage of said gas turbine to deliver thereto theexhaust gases from said internal combustion engine for further expansionin said gas turbine, said internal combustion engine and the auxiliaryprime mover being connected to said compressors to drive saidcompressors independently of said gas turbine.

21. Power generating plant as defined in claim 20 in which said internalcombustion engine and said auxiliary prime mover are free piston primemovers and said compressors are free piston compressors, said freepiston engine and said auxiliary prime mover and said free pistoncompressors respectively being constructed with two elementsoscillatable with respect to each other, given oscillatable elements ofsaid engine and said auxiliary prime mover and said compressors beingoperatively connected together and the other elements of said engine andsaid auxiliary prime mover and said compressors also being op=-eratively connected together to provide for 0s cillation of theconnected given elements and the connected other elements with respectto each other.

22. Power generating plant comprising means providing a combustionchamber for combustion of fuel therein, means for effecting combustionof fuel in said combustion chamber to produce gases at a predeterminedpressure substantially above atmospheric pressure, a main gas utilizingprimer move connected to said combustion chamber for utilizing the gasesdelivered therefrom to said prime mover substantially at saidpredetermined pressure to develop power in said prime mover by expansionof said combustion gases, means for compressing a combustion supportinggas to a pressure effective for delivering said gas to said combustionchamber against the pressure of the combustion gases therein, saidcombustion chamber being connected to said compressing means to receivesaid compressed combustion supporting gas therefrom without substantialexpansion thereof, means for developing from the combustion of fuelauxiliary gases at high temperature and at a pressure initially inexcess of said predetermined pressure, an auxiliary prime moverconnected to said auxiliary gas developing means for utilizing saidgases at high temperature and at said pressure in excess of saidpredetermined pressure to develop power therefrom by expansion thereofin said auxiliary prime mover to an exhaust pressure substantiallycorresponding to said predetermined pressure of said gases in saidcombustion chamber, said auxiliary prime mover being operativelyconnected to said compressing means for driving said compressing meansindependently of said main prime mover to effect said compression ofsaid combustion supporting gas, and means for delivering the exhaustgases from said auxiliary prime mover driving said compressing means tosaid combustion chamber to be delivered therefrom with and to cooperatewith said gases produced in said combustion chamber for developing powertherefrom in said main prime mover upon further expansion thereof fromsaid exhaust pressure.

ERNEST MERCIER. MARCEL EHLINGER.

References Cited in the file of this patent Number UNITED STATES PATENTSName Date Goinard Mar. 25, 1930 Baumann et a1 Mar. 5, 1935 HolzwarthOct. 19, 1937 Diedrich June 28, 1938 Anxionnaz June 17, 1941 New Dec. 1,1942 Kreitner Sept. 3, 1946 Planiol et a1 Nov. 19, 1946 Nettel et a1.Dec. 28, 1948

